<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>test</title>
</head>
<body>
<script>
    val = "123456"
    var isletter = /^[a-zA-Z]+$/.test(val);
    document.write(isletter);
    document.write("<br>");

    val2 = "asaaa"
    var isletter2 = /^[a-zA-Z]+$/.test(val2);
    document.write(isletter2);


    if (5 > 3) {
        var x = 'leg';
        alert(x)
    }
    
    alert("kiss "+x)
</script>
</body>
</html>